21416939 has 4 divisors (see below), whose sum is σ = 22107840. Its totient is φ = 20726040.

The previous prime is 21416909. The next prime is 21416953. The reversal of 21416939 is 93961412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21416939 - 2⁸ = 21416683 is a prime.

It is a super-2 number, since 2×21416939² = 917370552259442, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21416899 and 21416908.

It is not an unprimeable number, because it can be changed into a prime (21416909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 345404 + ... + 345465.

It is an arithmetic number, because the mean of its divisors is an integer number (5526960).

Almost surely, 2^21416939 is an apocalyptic number.

21416939 is a deficient number, since it is larger than the sum of its proper divisors (690901).

21416939 is an equidigital number, since it uses as much as digits as its factorization.

21416939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 690900.

The product of its digits is 11664, while the sum is 35.

The square root of 21416939 is about 4627.8438824144. The cubic root of 21416939 is about 277.7063432964.

The spelling of 21416939 in words is "twenty-one million, four hundred sixteen thousand, nine hundred thirty-nine".